CHEK2 and neoplasm: Notably, while both the ATM‐Chk2 and ATR‐Chk1 signalling cascades were activated to some extent in each and every case, there were five tumours that showed a higher level of ATR‐Chk1 axis activation compared to ATM‐Chk2 (cases no. 2, 3, 10, 15, 17 in Table 2), and the remaining cases displayed a comparable degree of ‘activity’ for both kinase modules (Table 2).